The CEMA publication that cdafd indicated in his/her first post does not have information that will answer your question. It mainly discusses tolerances and alignment of stringers, pulleys, etc.
The 6th edition of CEMA's Belt Conveyor for Bulk Materials (I realize you're dealing with packaged materials) noted that "the most widely recognized and accepted safety standard for conveyors, ASME B20.1 Safety Standard for Conveyors and Related Equipment" It also recommends ASME Standard B15.1 "Safety Standard for Mechanical Power Transmission Apparatus". Another document mentioned is ANSI Z244.1 "Personnel Protection"
I have a copy of B20.1-2003. It states "5.11.2(b)(1)When a conveyor that would cause injury when started is automatically controlled or must be controlled from a remote location, an audible device or devices shall be provided that can be clearly heard at all hazardous points along the conveyor where personnel may be present..."
B20.1 does not specifically address how to restart the motor (i.e. reset button), but rather refers the reader to ANSI Z244.1 and OSHA Standard 29 CFR 1910.147.
B20.1 can be bought here for US$50 (2006 version noted, I have the 2003 version)...
So, the company's safety committee doesn't consider a conveyor as being an industrial machine? It sounds like you're up against the wall when the safety committee won't even consider enhancements to personnel safety such as you have seen elsewhere and are, presumably, proposing to reuse at this site.
Good Luck,
CanuckMiner